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The climate of Virginia, a state on the east coast of the United States, is considered mild compared to other areas of the United States. Most of Virginia east of the Blue Ridge Mountains, the southern part of the Shenandoah Valley, and the Roanoke Valley, has a humid subtropical climate (Köppen climate classification Cfa), typical of the American South. In the mountainous areas west of the Blue Ridge, the climate becomes humid continental (Köppen Dfa) and maritime temperate (Köppen Cfb). Severe weather, in the form of tornadoes, tropical cyclones, and winter storms, impacts the state on a regular basis. Central Virginia received significant snowfall of 20 inches in December 2009.
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Climate zones
A lot of variations occur because of the state's significant relief. Elevations in Virginia vary from sea level to Mount Rogers at 5,729 ft (1,746 m) above sea level, with major gradations occurring at the edges of the Atlantic Ocean, the end of the Piedmont, and the Blue Ridge and Allegheny chains of the Appalachian Mountains. The moderating influence of the ocean from the east, powered by the Gulf Stream, also creates the potential for hurricanes near the mouth of Chesapeake Bay. Cold air masses arrive over the mountains, especially in winter, which can lead to significant snowfalls when coastal storms known as noreasters move up the Atlantic coast.
The interaction of these elements with the state's topography create micro-climates in the Shenandoah Valley, the mountainous southwest, and the coastal plains that are slightly but noticeably distinct from each other.
Statistics for selected cities
The highest recorded temperature is 115 °F (46 °C) at Balcony Falls on July 15, 1954 and the lowest recorded temperature is −30 °F (−34 °C) at Mountain Lake on January 22, 1985.
Severe weather
Severe weather is a concern in Virginia. Hurricanes make the coastal area of Virginia vulnerable. It is rare for a major hurricane to threaten the Virginia coast as hurricanes this far north tend to weaken due to cooler coast waters and increasingly westerly winds aloft. Heavy rain from tropical cyclones remains a concern, however. Hurricane Isabel in 2003 brought much destruction from wind and rain, killing 10 directly and doing nearly two billion dollars in damage. Hurricane Gaston in 2004 inundated Richmond after moving ashore South Carolina. Virginia is often struck with the remnants of systems which hit along the Gulf of Mexico coastline, which also bring torrential rain to the state. Hurricane Camille was an extreme example, bringing 27 inches (690 mm) of rainfall to portions of Nelson County in a matter of hours. Thunderstorms are an occasional concern with the state averaging anywhere from 35-45 days of thunderstorm activity annually.
Rainfall in Virginia is frequent, but does not normally get severe enough for floods. Virginia averages seven tornadoes annually, though most are F2 and lower on the Fujita scale. However, Virginia had eighty-five in 2004. Western Virginia has a lower rate of tornadoes.